Ontogenic change in the vertical swimming of East Asian common octopus Octopus sinensis paralarvae under different water flow conditions
Ontogenic change in the vertical swimming of East Asian common octopus Octopus sinensis paralarvae under different water flow conditions
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不同水流条件下东亚普通章鱼中华章鱼副幼体垂直游泳的个体发育变化
DOI：
10.1007/s10452-020-09777-7
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发表时间：
2020
期刊：
影响因子：
1.8
通讯作者：
Hamasaki Katsuyuki
中科院分区：
文献类型：
--
作者：
Dan Shigeki;Takasugi Arata;Shibasaki Shodai;Oka Masakazu;Hamasaki Katsuyuki
东亚常见的章鱼Octopus sinensis是一种底栖物种，但在生命的最初几周内会经历一个“休眠”阶段。由于海蛞蝓的游泳能力相对较差，它们的分散主要依赖于洋流;然而，垂直游泳可以通过控制它们在海流中的浮力来在水平分散中发挥重要作用。在这种情况下，个体发育的变化，在垂直游泳的环境水流的关键是了解的分散特性的dumarararabella和随后发病的解决方案，但这方面的信息仍然在很大程度上是未知的。本文以0、5、10和15日龄的中华绒螯蟹（O. sinensissparalartera）为实验动物，研究了不同流速（向下流速× 4，静止流速和向上流速× 5）对中华绒螯蟹垂直泳姿的影响。小于10日龄的Paralarabellus（干重< 3 mg）倾向于向上游，无论水流条件如何，但它们的游泳在向下水流下被打断，同时它们表现出重复的向上游和向下推回运动。因此，对于早期的游泳，向上的水流可能通过支持他们天生的向上游泳而对分散产生积极影响，而向下的水流可能由于过度游泳活动而导致的疲惫而对游泳产生负面影响。15日龄（> 5 mg）的Paralarabellus开始了短暂的附着行为，它们的游泳位置在白天分散向下，而不管水流如何，这表明开始向定居过渡。相比之下，它们的位置在夜间通过向上游泳移动到接近上限，即使在向下的水流下。我们的研究结果表明，O. sinensis hibits的特征行为，昼夜下降分散与附着（hyperbenthic性状）和夜间向上游泳（反张力性状）之间交替过渡到永久性底栖生活。
The East Asian common octopusOctopus sinensisis a bottom-dwelling species, but goes through a planktonic phase as ‘paralarvae’ during the first several weeks of life. As the swimming performance of the paralarvae is relatively poor, their dispersion relies primarily on ocean currents; however, vertical swimming may play an important role in their horizontal dispersion by controlling their buoyancy in the current. Within this context, ontogenic changes in vertical swimming in relation to the ambient water flow are key to understanding the dispersion properties of the paralarvae and the subsequent onset of settlement, yet this information remains largely unknown. Here, we investigated the effects of different water flows (downward × 4 velocities, stagnant and upward × 5 velocities) on the vertical swimming position in test columns using laboratory-raisedO.sinensisparalarvae aged 0, 5, 10 and 15 days during the day and at night. Paralarvae younger than 10 days (< 3 mg in dry weight) tended to swim upwards regardless of the water flow conditions, but their swimming was disrupted under downward water flows, while they exhibited repeating upward swimming and downward pushing-back movements. Thus, for early paralarvae, an upward water flow may have a positive effect on dispersion by supporting their innate upward swimming, while a downward water flow may impact paralarvae negatively due to exhaustion through excess swimming activities. Paralarvae aged 15 days (> 5 mg) commenced short clinging behaviour, and their swimming positions dispersed downwards during daytime regardless of the water flow, indicating the onset of the transition to settlement. In contrast, their position shifted to near the upper limit at night by swimming upwards, even under downward water flows. Our results suggest thatO.sinensisexhibits characteristic behaviour that alternates between diurnal descent dispersion with clinging (hyperbenthic trait) and nocturnal upward swimming (planktonic trait) during the transition to permanent benthic life.